A brief pre-maximum peak in the Quadrantids 2020

The main maximum of the visual Quadrantids occurs annually with very little variation at solar longitude 283.15 +/- 0.04 degrees. In 2020 this position was reached on January 4 near 08 UT, thus favourable for North American longitudes. Observations of the ascending branch showed a short peak at solar longitude 282.880 degrees (2020 January 4, 02 UT). This peak is found in visual and radio forward scatter data. The position and duration perfectly coincides with a pre-maximum peak observed in 2016. Analyses of data from the period 2004 - 2020 show similar peaks in 2008, 2009, 2014, 2016 and 2020. The 2008, 2016 and 2020 peaks occurred very close to solar longitude 282.880 degrees within +/-0.02 degrees, while the 2009 and 2014 peaks are 04 and 008 earlier, respectively. Further, we summarize the Quadrantid main maximum ZHR and positions for the period 2004 - 2020.